Magician and endurance artist David Blaine hangs upside down in New York City's Central Park. Blaine said he would stay in that position for 60 hours. Simple as it may sound, the stunt could easily have killed him, doctors said. The constant rush of blood to his brain for so many hours could have left him blind, or worse, given him a stroke. Clearly Blaine wasn't exaggerating when he said he felt like his head was 'about to explode' in an interview.